CB col touch rifling or jump?

[TargetShow]

Hello,
New member here. 1st I do not cast, but I'll be loading some Cast for a rifle for the first time and testing this weekend. I have been reloading jacketed for about 5 years.

I am loading some reduced loads and subs with Oregon trail cb for my 308, and was wondering What most people had the best luck with, loading touching lands or jump? I will try both but I was curious if people usually had better luck with one or the other.

[aspangler]

10 thousands or less but not quite touching works best for me but YMMV.

[TargetShow]

Thank you for input aspangler, much appreciated

[.22-10-45]

In my Shillen barreled Sharps-Borchardt Hornet, I have found best accuracy after making a tapered sizer die to size 1st. band to match taper & dia. of throat/leade angle. 1st. band fully engraved on closing action.

[Slow Elk 45/70]

Depends on what your rifle likes, some shoot better with boolit touching the lands, some like a bit more "jump" as you call it , some like to be engraved.....so it depends on your BBL...test and see..IMHO

[facetious]

I have mold from LBT for a 170 lfn .30 cal. that I have been playing with. When I found a lode that shot good with the bullet just touching I tried seating it deeper .010 at a time and found it shot better .050 from the lands.

[TargetShow]

Thanks a lot every one.
This is the bullet I will be trying.
http://img.tapatalk.com/d/14/02/06/eby5e4y8.jpg

[Jim Flinchbaugh]

I've had my best luck with a bore rider design for rifles. Sized so the front band just fills the throat and the nose
lightly engraves upon seating. Boolit is seated so the front band just touches the rifling.
If it is slightly snug on the nose and fills the throat, it should shoot- its what works for me so far.

[Blammer]

looks like you'll need a GC on the bottom of that bullet.

[xacex]

They sized and lubed, but didn't bother to put a gas check on? There are going to be some newly leaded guns at the local pawn shop.

[TargetShow]

I have gas checks on the way. Are you saying I can't shoot them without?

[DougGuy]

You'd be much happier using them.

FWIW, my 308 likes about .020" freejump with jwords, I can get 3 into a guitar pick @200yds. I haven't brought it around to cast yet.

[TargetShow]

Oops I misread xacex post at first I thought it was gonna ruin my gun, but leading ain't good either

[TargetShow]

These will be reduced and sub loads , I was hoping leading wouldn't be bad, but I got lots to learn

[Scharfschuetze]

I think that you'd be OK if you keep the velocity down to around 1200fps without a gas check on that bullet. You might also try something like Cream of Wheat as a filler to protect the base of the boolit from gas cutting for a little more velocity. If you do though, be sure to add the weight of the COW to your boolit weight for the total ejecta weight when starting your load work up.

Due to deployment schedules following 9-11, I bought a lot of pre-cast boolits in order to maximize my shooting when at home and I shot a lot of the Oregon Trail boolits, including the one you propose to use. They definitely perform best with gas checks on 'em at 1700 to 1900 fps. They are an awfully hard boolit and my best loads with them in a 30/30 use a gas check at around 1800fps. To be honest, I think that they can be driven faster than that; I just haven't felt the need to do so.

The particular lot that I bought (several thousand) have a shank that has a fairly wide diameter. Due to that, I initially seat the gas check with an arbor press with the bullet set on a steel block so that there is no tilt to the initial seating. Once initially on, I then crimp it into place with an RCBS Lube-A-Matic. The Lube-A-Matic (with my lot of boolits) just doesn't have the leverage needed to initially properly seat the GC without straining the linkage. I've also often thought about somehow dissolving the crayon lube and using NRA 50/50 with 'em, but I've not got around to that yet; probably because I can cast my own Lyman 311041 (similar design) and lube 'em up as I want to begin with.

I've not played around with seating depth for accuracy purposes as they shoot well enough out to 220 yards for me. I just crimp the cases into the crimping groove so that they will function through the magazines of my rifles.

I've not tried this design in the 308 with its short neck, as you soon will, but I think that I'd try and keep the base of the boolit above the shoulder while still being able to chamber the round if that's possible. If not, try for a tight fit of the GC to the shank of the boolit.

That said, I've enjoyed good accuracy with them in an 1893 Marlin rifle (circa 1903) and a model 94 Winchester (circa 1956) carbine, both of which will shoot this boolit into 10 shot groups that hover around 2 1/2 MOA out to 200 yards. I think that they are cast pretty well as they enjoy a minimum of variation in weight from boolit to boolit and I rarely see an obvious flyer in my groups.

Good luck and keep us posted.

[DougGuy]

Something else that works is a wax gas check. I get dental wax in sheets .060" thick and cookie cutter them onto the brass, push them down while seating the boolit. I use these with plain base boolits in .45 Colt that I shoot heavy boolits to max loads in and they work. In a bottleneck cartridge, you wouldn't want it falling down on the powder but if you can get a wax cup around the gas check shank of the boolit and it will stay on, they will work until your regular checks arrive.

[TargetShow]

Thanks a lot for input everyone.
My max col seating depth is going to put the transition to gas check diameter right at neck/shoulder junction. As far as seating gas checks I didn't figure it would take that much pressure, my lee challenger probably isn't up to task , the linkage isn't impressive.

[geargnasher]

I was going to say what Slow Elk already did.

Nice thing about cast (in bolt-action or single-shot rifles) is you can jam them and not raise pressure much, unlike with jaxketed. With any rifle it's a box of chocolates until you load a few to different depths and start pulling the trigger. No "rules" here except autoloaders don't function well with the boolit jammed in the lands. Not good for field use, either.

Gear

[cbrick]

Your action type/chamber could well pre-determine this for you but almost across the board my single shots and bolt actions do their best when slightly engraving. As already mentioned though, there are no set in concrete rules so you'll need to test various loaded lengths and let your gun tell you what it likes with each boolit.

Rick

[TargetShow]

Well I shot 10 rounds out back today of the 170 rnfp without gas check seated to just barely off lands. First I weighed a full scoop of 2.8 cc lee dipper that came with my 308 die set, it weighed 12.8 gr. per imr trail boss universal reduced load formula my load min fell at 10.15gr and max 14.5gr. Being reduced loads I was comfortable to use the dipper for simple 12.8gr loads.
Shot 4 through chrony 12 degrees 650 alt.
1st 1434 fps
2nd 1469
3rd 1464
4th 1464
This was done directly after cleaning barrel.
I shot 6 into a stump at 50 yards and it appears they shot about 1 moa. I am happy thus far but will get a better idea Sunday and or Monday at range.
I really not good at reading lead deposited. I tried to take some pics. Can any body tell anything by these? Bore is soaking with kroil right now, but no flakes came out with initial patches.

http://img.tapatalk.com/d/14/02/08/ru6adere.jpg
http://img.tapatalk.com/d/14/02/08/ebune4ym.jpg

[xacex]

If they are properly sized, and not .308 a reduced (plinker) load with a slower powder would work without the check. But, if they sized them at .308 you are better off putting on a gas check anyway. If you decide to try it out without checks shoot no more than 10 and check the bore. If you see leading stop before it gets unbearably leaded. It is not fun cleaning lead from a barrel. Heck, if it were me I would melt of the lube, soak in solvent and powder coat them. No check needed then unless you are going full bore with the load.

From your pic's it looks ok, shoot another batch this time upping it to 20. Your speed is a little fast for what I would shoot a boolit without a gas check, but if it works go for it. Just be cautious and watch for leading every now and again. Nice lube star btw..

[TargetShow]

Thank you for input xacex and mentioning lube star ring, what would a lead ring look like in comparison? I have 20 cases that are fire formed (these were too), ill load them same exact way and keep eye on leading. I'll also full length some and try similar load, I need to fire form for neck sizing anyway. Anxious to see how they perform at 100+. Sure would be nice of I could get away without gas checks, while keeping leading to minimum. I wanted to load these down to sub level as well, but these are pretty hard cast and I read somewhere that too slow and too hard could be a leading problem at chamber end. For now I'm gonna keep shooting same load as above as I learn more.

[mpbarry1]

No leading at the end of the barrel. did you get a lube star at the muzzle? with reduced loads i would be more concerned w leading in the throat. those LCs are hard and need a little pressure to obutrate to the lands.

[TargetShow]

I believe it was a lube star as xacex noted above, but I failed to inspect if well before I began running kroil patches down bore and wiped of muzzle. I am concerned about throat area as well with current load, it Is hard to get a good look in throat though.

[TargetShow]

The bullets are .310 btw